Nieminen, a two-time finalist in the indoor tournament, won eight straight games en route to a 6-0, 6-4 victory over Peter Luczak, and Ancic beat Bjorn Rehnquist 6-1, 6-3.

Nieminen, who has lost just seven games in his first two matches, faced six break points during the match and saved them all. In the first set, the Finn lost only eight points.

"It feels very good to win," Nieminen said. "I was the favorite in this match, and lost only a few games. I played the first set almost perfectly."

Nieminen, seeded sixth, will play either top-seeded James Blake or Frank Dancevic in the quarters. Last year, Nieminen lost to Blake in the final. Nieminen also was a finalist in 2001.

The hard-serving Ancic, playing only his fifth tournament since February, never faced a break point against the 306th-ranked Rehnquist, who got into the main draw as a lucky loser after the qualifying event last weekend.